Process of cutting self-hardening steel.



No. 779,516. PATENTED JAN. 10, 1905. J. ARMSTRONG. PROCESS OF CUTTINGSELF HARDENING STEEL.

APPLICATION FILED MAR. 21, 1904.

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Patented January 10, 1905.

PATENT OFFICE.

JOHN ARMSTRONG, OF CHICAGO, ILLINOIS,

ASSIGNOR TO ARMSTRONG BROS. TOOL CO., A CORPORATION OF ILLINOIS.

PROCESS OF CUTTING SELF-HARDENING STEEL.

SPECIFICATIONforming part of Letters Patent No. 779,516, dated January10, 1905. Application filed March 21,1904. Serial No. 199,221.

1'0 (tZZ whom it may concern:

Be it known that I, JOHN ARMSTRONG, a citizen of the United States, anda resident of Chicago, county of Cook, and State of Illinois, haveinvented certain new and useful Improvements in Processes of CuttingSelf-Hardening Steel, of which the following is a specification,reference being had to the accompanying drawings, in which Figure 1represents a front elevation, Fig. 2 a side elevation, and Figs. 3, 4, 5details, of a machine for carrying out the process; and Fig. 6 is an endview of a bar of metal, showing the work of the machine.

The invention relates to the cutting of that metal known in the trade asself or air hardening steel and which is used for machinetools- Thissteel is customarily supplied by the manufacturer in bars of a suitablesection for tools, but of a length sufficient for a number of tools, andit is necessary for the consumer or the maker of tools to out these barsinto a number of short pieces. This self or air hardening steel is ofsuch an extremelyhard nature that it is impossible to cut by anyordinary means, such as a hack-saw or toothed cutter of any description.It is also very expensive, and heretofore great waste of time andmaterial have resulted from the lack of some quick and practical methodof cutting off this character of steel in a cold condition. The commonpractice has been to heat the bar-steel in a forge and cut it with achisel and sledge while hot or to cut it partly through with anemery-wheel and then break it; These methods, however. have resulted inloss both of time and material.

The present invention is designed to avoid this waste of time andmaterial incident to the methods previously mentioned; and it has forits object to provide a process for cutting off bars or rods of thisclass of steel quickly and accurately while cold.

The process consists in cutting into the bar of steel by means of arapidly-revolving disk of tool-steel having initially a smoothperiphery. Preferably a shallow kerf is thus cut across each face of thebar, when it may be broken over an anvil, the fracture being confined tothe plane of the kerfs.

In the accompanying drawings, A is a rotatable disk of tool-steelsupported by the heavier disks Z) I) and rigidly fixed to the shaft 0 bymeans of plates (Z (Z and a nut f. The belt-pulley O provides means forrapidly r0- tating the shaft 0 and the disk A. The frame M serves tosupport the rotating parts just described, as well as a work-table Tcapable of being moved to and fro under the disk. Projecting from thebottom of the work-table T is a slide t, which engages the upper portionof the upright m and provides means for raising and lowering the tableto accommodate diflerent sizes of work, this adjustment being made bythe screw S. The upright m is pivoted to the frame M to provide for theoscillating movement of the work-table under the disk. Anexpansion-spring P returns the work-table to its normal position aftereach advance to the cutting-disk. The work-table is provided with aguide or stop 9 to facilitate the adjustment of the bar or rod on thetable in order that pieces of uniform length shall be cut off.

In carrying out this process the bar or rod to be cut is placed on thetable and firmly held against the strip 0 and the stop 9, and the tableis pushed forward and under the disk, whereby the incision (shown byFig. 6) is made. After the return of the table to its normal positionthe bar or rod is turned over a part of a turn and the operationrepeated, and so on until several incisions have been made around thebar. The depth of the incision can be varied by adjusting the height ofthe work-table.

The cutting-disk is made of tool-steel and is preferably about onethirty-second of an inch in thickness and eighteen inches in diameter.The saw is preferably slightly dished in order that a clearance will beprovided. In practice the disk is rotated so as to have a peripheralspeed of between two and three miles a minute. It has been found thatthe disk will not cut materially until its edge has been suit- Thispreparation consists in ably prepared.

rotating the disk for some time with its edge in contact withself-hardening steel, the cutting quality of the blade graduallydeveloping, the initial effect being a mere abrasion of the material.After being thus treated for one or two hours the blade will cut intothe material readily. NVhile I am not prepared to suggest the details ofthe theory of the operatioml suppose it to be a fact that the rim of thesaw becomes charged with minute particles of the self or air hardeningsteel and that these particles constitute the saw-teeth or abradingagents.

During the operation of cutting, grains of self-hardening steel arethrown out by the disk, the sawdust remaining in the form of loose orseparate grains, clearly indicating the sawing to be accomplished by atrue cutting action as distinguished from the fusion set up by so-calledcold-sawing, as practiced heretofore.

I claim as my invention 1. The method of cutting self or air hardeningsteel consisting in applying to it the rim of a rapidly-revolving diskof tool-steel which has been subjected to abrasive contact with self orair hardening steel.

2. The process of cutting self or air hardening steel, consisting infirst treating the rim of a metal disk by impinging it while in rapidrotative movement against a mass of material having the character ofself or air hardening steel, such treatment being continued for aconsiderable period of time, then applying the disk edge, While rotatingat high speed, to the surface of the material to be cut and passing itinto the body thereof.

JOHN ARMSTRONG.

Vvitnesses:

PAUL ARMSTRONG, LoUIs K. GILLsoN.

